This is Tim's tattoo.
This tattoo is a quote from Fahrenheit 451 by Ray Bradbury.
"A book is a loaded gun in the house next door. Burn it. Take the shot from the weapon. Breach man's mind. Who knows who might be the target of the well-read man?"
I have always felt that the more well-read a person is, the more he can control his/her own life without the aid of others who may choose to use a gun instead of a book.